A free email agroforestry journal for practitioners, extension agents, researchers, professionals, students, and enthusiasts. One edition is sent each month focusing on a concept related to designing, developing, and learning more about trees and agroforestry systems. Focuses on trees and their roles in agriculture, natural ecosystems, human culture and economy.

Traditional Yapese farming system with a diversity of annual and tree crops

Introduction

It has been estimated that approximately 1.2 billion farmers practise agroforestry, while about 1.5 billion people (over 20% of the world’s population) use agroforestry products. From my travels seeing a wide range of different agroforestry systems, I realized that agroforestry is more than just an agronomic practice that restores soil fertility and produces tree products in farmers’ fields. It is also applied ecology or, more accurately, applied agroecology – the ecology of farming systems. This means, therefore, that it could be expected to also deliver ecological functions over and above such environmental services as erosion control, water infiltration, provision of shade, etc. that we saw in the last chapter. Environmental services are basically physical processes, while ecological functions have to do with the biological processes that make ecosystems dynamic and that regulate the balance between different organisms. This ecological balancing act is all about regulating the interactions between organisms throughout their life cycles and along their food chains. So, this process is an altogether higher order of magnitude in the way life self-regulates and creates a balance between species. It is this balance that confers ecological sustainability in different types of vegetation, landscapes or land uses.

Wick irrigation can greatly increase water use efficiency, which is especially needed in regions with severe water scarcity. In this photo, different wicking materials are evaluated for capillary rise, gravity flow and wetting rates.

The world’s 500 million resource-limited farmers are facing ever more difficult challenges in growing sufficient food and products for sale with inadequate water supplies (Hazell et al., 2007). These farmers face difficulties in locations where the climate is moderate but rainfall is seasonal, and endure far more severe problems in arid and semi-arid regions where rainfall is scarce and unpredictable. Climate change, including increased climate variability, is expected to worsen the problems these farmers and gardeners face by raising the temperature and reducing rainfall. The severe 2011-12 drought in Mexico illustrates what we may expect in the future (Figure 1, NOAA, 2012). The global maps of predicted chances are equally daunting.

Introduction

Perennial Staple Crops are basic foodstuffs that grow on perennial plants. These plant sources of protein, carbohydrates, and fats can be harvested non-destructively -- that is, harvest does not kill the plant or prevent future harvests. This group of crops includes grains, pulses (dry beans), nuts, dry pods, starchy fruits, oilseeds, high-protein leaves, and some more exotic products like starch-filled trunks, sugary palm saps, and aerial tubers.

Perennial homegarden on sloping land in Bali. Such time-tested systems exemplify the multiple functions of perennial agriculture.

Introduction

Unlike expensive geoengineering approaches to slowing climate change, regenerative perennial agriculture is remarkable in addressing many of the challenges facing humanity today while sequestering carbon. Were humanity to prioritize this strategy to stabilize our climate, we would reap many other benefits and help address challenges from erosion to food sovereignty.

Introduction

Humans have cultivated plants in a number of different arrangements for thousands of years, including mimicking forest growth to create agricultural systems that can be categorized as “multistrata homegardens.” Homegardens are “intimate, multistory combinations of various trees and crops, sometimes in association with domestic animals, around the homestead” (Nair & Kumar, 2006). Homegardens are most prevalent in the tropics—e.g., South and Southeast Asia, Pacific Islands, East and West Africa, Mesoamerica—but also exist to a much smaller degree in temperate zones of China, North America, and Europe (Nair & Kumar, 2006). Homegardens have been cultivated in tropical regions across the globe for centuries, or even millennia in some cases, and continue today to be a major source of valuable and nutritious food, fodder, medicine, fuel, and building materials. In addition, homegardens can deliver intangible benefits to owners and caretakers, such as beauty, quietude, and a sense of pride, hope, and self-confidence, especially as the homegardener experiments, adjusts, and learns through the process of establishing and maintaining a multi-functioning homegarden (Katanga et al., 2007). Finally, homegardens serve as both planned and associated biodiversity repositories (Montagnini, 2006), and they also sequester carbon.

Introduction

In the broadest sense, insects have enormous economic value in terms of the ecological services they provide. A recent study in the United States, for example, found that the annual value of insects’ services amounted to more than US$57 billion. The study found that native insects are food for wildlife that supports a US$50 billion recreation industry, generate more than US$4.5 billion in pest control and pollinate crops worth US$3 billion (Losey and Vaughan 2006). If such a study were expanded to include the entire world, the total figure indeed would be staggering.